Method of producing waterproof coatings on objects which are influenced by humidity.



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METHOD OF PRODUCING WATEE: ROOF CUAT'TNGS 0N OBJECTS WHICH A INFLU- ENCIEJD BY HTTT.

Ito Drawing.

To all whom it may concern:

Be it known that T, MAX DICKERT, a subject of the German Emperor, residing at Verne, in the Province of Westphalia, Kingdom of Prussia, and German Empire, have invented certain new and useful Tmprovements in Methods of Producing Waterproof Coatings on Objects Which are Influenced by Humidity, of which the following is a specification.

My invention relates to a method of producing a very thin coating which renders the objects provided therewith absolutely indifierent to humidity. Although this method is fit for quite general purposes, the same is in particular very well adapted forcoating the cartridges of sporting guns which are provided with a card-board casing.

My improved method is preferably carried out in the following manner: The object to be provided with said coating is first dipped into a solution of gutta-percha or balata, for example, in benzol, bisulfid or tetrachlorid of carbon, either colorless or colored by means of' a dye, said solution be ing preferably heated to a suitable temperature. In this way said object obtains a thin Y coating of-said substance. Now the object is provided with a coating of cellulose ace tate. To attain this end said object is dipped into a suitable solution, for instance, a soll1- tion of cellulose acetate in chloroform or nitrobenzol. After vaporizing the solvent,

the object is heated about half an hour to a point above the degree of temperature at which the balata or gutta-percha becomes plastic, 2'. 6. begins to melt. Y

My improved method is based upon the following considerations: Neither balata nor gutta-percha is quite waterproof in small layers. This is not the case for cellu-. lose acetate. Further, neither balata nor gutta-percha is indifierent to: air. Consequently, the second coating composed of cellulose acetate has a double. purpose. First, said coating of cellulose acetate is intended to close the pores contained in the balata or gutta-percha layer; and secondly it has for its purpose to protect said coating of balata or gutta-percha against the action of air. The combined coating becomes quite waterproof only on being heated above Specification of Letters Patent.

the temperature at which the first layer or coating becomes plastic or semi-liquid, because, owing to the fact that the balata or gutta-percha layer begins to melt, all the pores which may still exist become closed. In consequence thereof the purpose of protecting the object to be treated against the action of humidity, for example in the case of cartridges provided with a card-board casing against swelling, is to a great extent attained by the co-action of both layers or coatings; however, the efi'ect obtained is principally due to the above mentioned fact that the heating takes place to such an extent that the layer of balata or guttapercha assumes a semi-liquid condition so that the same can flow and in consequence thereof is able to fill up the pores of said not completely protect the objects, for example cartridges, against humidity, and also paraflin has the drawback that cartridges coated therewith soils the gun-barrel after repeated shooting. Lastlyfltwish it to be well understood that, when in the claim T shall speak of balata alone, gutta-percha or a mixture of both is also meant as equivalent for gutta-percha.

W What I claim and desire to'secure by Letters Patent of the' United States is A method of producing a waterproof coating on objects which are influenced by humidity, such as gun-cartridges provided with a card-board casing, which consists in first providing the object with a layer of balata andsecondly with a layer of cellulose acetate and then in heating the object above the temperature at which the first layer becomes semi-liquid or able to flow so as to fill up the pores of said first-layer.

In testimony whereof I aflix my signature in presence of two witnesses.

a woman [as] Patented hpr. 25, rate...

Application filed 1T uly 30,1915. Serial No. 42,826. 

